I have a toy chinanwona weight 1 p and a half he is 16 month old he is throw up and not drinking or eating he has not been out in the heat he isn't trying any food.acts like he doesn't have any enengy.

My maltese had the same problem about 7 months ago and I'm going to tell you now don't waste your money on the vet just take a straw and fill it with water then open your dogs mouth and pour it in take some eggs (its good 4 dogs) and hard boil them mix the yokes with water and mash them together till its liquidy enough to put into a straw and give it to him the same way you did this with the water slowly give lots of water to it through the day and about 4 times a day with the eggs and slowly your dog should eat again. :)
Hope this helped. :)

This could be many things from low blood sugar to parvo to obstruction.
The only real way to know is to get him to the vet.
In the meantime rub a little Karo syrup or pancake syrup (whatever you have on hand)
On his gums to boost his sugar.
You can try gatorade or pedialyte to keep him hydrated, but my suggestion is to get him to the vet ASAP.
At 1 lb 8 oz he will dehydrate very quickly, puppies tend to go downhill quickly without the proper treatment.